P1639

P1639-TCM INTERNAL-CAN 2 RAM PERFORMANCE






For a complete wiring diagram, refer to: Electrical Diagrams

Theory of Operation
The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. This DTC indicates that there is an internal error with the controllers Random Access Memory (RAM) on the CAN controller 2 section of the microprocessor. If detected, the controller will enter Limp-in mode and illuminate the MIL.

When Monitored
Continuously with the ignition on.

Set Condition
If the TCM detects an internal error with the controllers Random Access Memory (RAM) on the CAN controller 2 section of the microprocessor.

Possible Causes
- TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test
1. TRANSMISSION CONTROL MODULE
View repair

Repair
Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM per the Service Information. Refer to - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE for the appropriate service procedures.
Perform NAG1 TRANSMISSION VERIFICATION TEST - Ver 1. Verification Tests